JP4526738B2 - Geological exploration method of existing tunnel and maintenance management method of existing tunnel using it - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to maintenance management technology for accurately performing necessary maintenance work for the purpose of appropriately maintaining existing tunnels and ensuring safe traffic, or prior survey technology for construction such as tunnel widening work, Conduct geological surveys of existing tunnels while maintaining the operational status of existing tunnels, and perform necessary maintenance measures or widening of existing tunnels based on the results of such geological surveys.
[0002]
[Prior art]
Japan has many mountainous areas, and railroads and highway networks run through the mountainous areas. Therefore, there are many tunnels that are indispensable for daily traffic. In addition to mountain tunnels, there are also submarine tunnels that connect sections separated by straits.
[0003]
In many of such existing tunnels, a large amount of concrete is used as lining concrete that covers the inner peripheral surface of the tunnel, and supports the safety of the tunnel structure. The existing tunnel naturally deteriorates over time, so the necessary maintenance work such as repairing cracks in the concrete surface of the lining concrete and filling in the cracked concrete part is appropriately performed, and traffic safety is achieved. . Precautions are taken in advance by knowing in advance the expected location of peeling by means of visual inspection, hammering, etc., using a patrol or the like.
[0004]
In the problem of deterioration of existing tunnels, the internal factors depend on the quality of concrete itself and the construction method. The external factors are the flow and inflow of groundwater based on changes in ground conditions, the amount of traffic in the tunnel, The accompanying vibration is considered. Among them, external factors based on the natural conditions of the existing tunnels are considered to be the main causes. For example, depending on the natural conditions (geological conditions), natural strength over time (deterioration, weathering, etc. Acceleration of lining concrete deterioration due to infiltration and softening associated with groundwater flow.
[0005]
For this reason, when performing appropriate maintenance work, it is necessary to determine whether the cause is an external factor or an internal factor in determining each situation. For example, it is necessary to determine whether the deterioration phenomenon such as peeling of the lining concrete is based on ground conditions that are in direct contact with the lining concrete or based on causes that are completely unrelated to the geological conditions such as traffic volume. It is.
[0006]
As for maintenance management of existing tunnels, soundness diagnosis of concrete including lining concrete, connectivity with concrete ground (such as whether there is a cavity between concrete and surrounding ground), concrete, etc. Approaches from various viewpoints such as research on repairing materials and research on concrete materials (chemical deterioration, material characteristics, etc.) are required, and measures that integrate these are desired.
[0007]
In this way, regarding the problem of tunnel degradation in the maintenance management of existing tunnels, whether it is a problem due to the above-mentioned concrete material or the environmental conditions of the tunnel, or a problem related to ground conditions such as crushing zone, degradation, stress release, etc. It is important to select an appropriate solution by clearly dividing it and trying to solve it according to the problem situation.
[0008]
As mentioned above, it is extremely important to ensure that daily traffic can be performed safely by appropriately maintaining and managing existing tunnels. However, existing tunnels are no longer suitable for current traffic conditions. In some cases. In the current situation judgment based on the maintenance management of existing tunnels, there is a case where a tunnel having a scale suitable for mass traffic may be required based on the predicted increase in traffic volume in the future rather than performing maintenance management of the current situation. In such a case, it is necessary to consider the construction of a new tunnel other than the existing tunnel or the widening of the existing tunnel.
[0009]
However, in reality, it is more advantageous to widen the existing tunnel to a large tunnel than to create a new tunnel due to various factors such as the problem of construction limits, economics, construction conditions, and the effect on the surrounding environment. In recent years, widening work for existing tunnels is increasing.
[0010]
[Problems to be solved by the invention]
Regarding the maintenance management of existing tunnels, as described above, it is necessary to determine whether or not the problem at hand is related to the natural conditions. However, the existing tunnels are usually in a situation where the geological data on the ground conditions of the tunnel cannot be fully utilized, and it is not possible to fully grasp the ground conditions.
[0011]
Regarding tunnel ground conditions, at the time of tunnel planning, elastic wave exploration (refraction method) and boring survey are conducted from the surface side and used as design data. Furthermore, the construction is proceeding while confirming the actual geology of the tunnel construction site through observation of the working face and various measurements during construction. For this reason, the cause of tunnel degradation should be isolated by using such geological survey materials for maintenance management after completion of the tunnel.
[0012]
However, in existing tunnels that have passed for a long time after construction, such materials are scattered, so such materials cannot be fully utilized for maintenance and management, and there are cases where the cause of tunnel deterioration cannot be substantially isolated. is doing.
[0013]
In addition, it is fully conceivable that the surrounding ground after the opening of the tunnel changes over time, leading to a deteriorated geological situation different from that at the time of construction, and the cause of the deterioration of the tunnel may not be determined quickly.
[0014]
In this way, in the field of maintenance management at the site, it is sufficient whether the case where there is a problem with the concrete itself as described above or the case where it occurs because there is a problem with the ground condition in analyzing the cause of the tunnel degradation site. There are many cases in which it is difficult to make appropriate cuts and the necessary information for maintenance measures cannot be obtained.
[0015]
Even when the results of geological surveys at the time of such construction cannot be fully utilized, it is necessary to grasp the geological situation where the tunnels are located from the tunnel mine in order to manage the safe passage of the tunnel. As a conventional geological exploration method, a TSP method and an HSP method using blasting as a vibration source have been proposed, but such a method can be applied during tunnel construction. The above-mentioned method of conducting geological exploration based on blasting vibrations in an existing tunnel that is actually opened and is routinely conducted is not a realistic exploration method.
[0016]
In addition, as a method that does not use blasting as a vibration source, for example, there is an elastic reflection method using high-voltage plasma as a method applied at the time of tunnel construction. In this exploration method, it is necessary to bring a large transformer into the tunnel and generate a high voltage in the tunnel. Unlike tunnel construction, even if thorough traffic regulations are implemented, there are concerns about unforeseen accidents due to stray currents based on high voltage, and it is difficult to adopt as a geological exploration method for existing tunnels. .
[0017]
The above-mentioned method proposed as a geological exploration method for tunnels is an exploration method that is necessary when constructing tunnels. As explained above, for the geological exploration of existing tunnels that are used on a daily basis, It cannot be easily applied from various viewpoints.
[0018]
In tunnels that are used on a daily basis, especially in tunnels with a large amount of traffic, it is necessary to avoid traffic restrictions even if temporarily, although it is for geological exploration. In road tunnels, such as railway tunnels and road tunnels that do not have appropriate detours other than using the tunnel, the impact of traffic restrictions is extremely large, and in some cases, it may have a significant impact on the local economic activities. Fully assumed.
[0019]
In such a situation, the above conventional method cannot be easily adopted, and when it is considered that there is a problem in the ground condition, a method of investigating the point by a boring survey or the like has been conventionally adopted.
[0020]
However, the actual situation is that it is very difficult because the work is limited in the tunnel in service. Moreover, the data obtained by the boring survey is only data of a certain point (point), and is not information on the ground across the entire tunnel from the tunnel head on one end side to the tunnel head on the other end side.
[0021]
Furthermore, it is theoretically possible to conduct a boring geological survey over the entire tunnel, but depending on the total line distance of the tunnel, an extremely large number of boring points must be set, Enormous costs are incurred, and it is not a realistic exploration method.
[0022]
In such a field situation, peeling of lining concrete has occurred in recent years, which has become a major social problem. By using non-contact and non-destructive investigation methods, the ground conditions of the entire tunnels of existing tunnels that are actually used can be explored safely and easily without greatly affecting the utilization status, and the results of the investigation Based on this, it is urgently necessary to formulate appropriate countermeasures against tunnel degradation.
[0023]
On the other hand, in parallel with the problems in the maintenance management of the existing tunnel, in consideration of the current status of the existing tunnel and the future traffic increase, widening work was also included from the viewpoint of maintenance management costs required to maintain the current status. In some cases, it may be necessary to renew existing tunnels.
[0024]
Considering recent traffic conditions, traffic of large vehicles has increased compared to the past, and the existing tunnels have been widened to large tunnels in consideration of problems of construction limits, economy, construction conditions, surrounding environment, etc. The number of constructions to be increased is increasing. When a new tunnel is provided in addition to the existing tunnel, various problems including land acquisition are involved, and it is difficult to take early action. The widening of the existing tunnel is easy to take early measures, unlike the case of such a new tunnel. Such widening work requires geological information on the widening side of the existing tunnel.
[0025]
In tunnel construction, geological surveys are carried out at the planning and design stages, and drilling is carried out while investigating the tunnel geology through face observation and various measurements at the time of construction. Often no geological information is available. In particular, there are many cases in which various materials are not available at all in tunnels with an old construction period (for example, tunnels that have passed over 30 years since construction).
[0026]
In addition, even if there are existing survey results, there are many cases that do not match the current technical level (investigation method, tunnel excavation method). In this case, it is desirable to conduct a survey that conforms to the current technical level. It is. As described above, in the widening work of the existing tunnel, a new investigation on geological information such as the surrounding ground condition is required, as is required for the maintenance management measures.
[0027]
Regarding the geological survey of such existing tunnels, the same problems as those associated with the geological survey conducted when isolating the influence of the ground conditions for the maintenance management occur. In other words, there may be problems such as conducting surveys under livelines while minimizing traffic restrictions, and drilling geological surveys.
[0028]
Therefore, as a geological exploration technique for the widening work of the existing tunnel, a technique for exploring the ground condition of the whole tunnel of the existing tunnel safely and easily without greatly affecting the use situation is preferable. It would be desirable if a technique for exploring the condition of the ground in the widened part of the tunnel could be applied by a non-contact / non-destructive investigation method.
[0029]
In addition, if geological information is obtained by this method, it is possible to confirm an appropriate boring point even if a situation in which a boring survey is used together for further investigation.
[0030]
An object of the present invention is to perform geological exploration in an existing tunnel while minimizing tunnel traffic restrictions.
[0031]
Another object of the present invention is to make it possible to easily perform geological exploration without disturbing tunnel traffic even in existing tunnels where geological data cannot be used, and to perform sufficient tunnel maintenance management based on the results. It is in.
[0032]
Another object of the present invention is to perform geological exploration easily without obstructing tunnel traffic even in existing tunnels where geological data cannot be used, and based on the results, can be applied to preliminary investigations such as widening construction of the tunnel. There is to be able to do it.
[0033]
[Means for Solving the Problems]
The geological exploration method for an existing tunnel of the present invention is a method for exploring the surrounding geology of an existing tunnel after opening, Ensuring that one side lane in the existing tunnel can pass vehicles, etc., on the other lane side in the existing tunnel, A plurality of vibration receiving devices are installed at a predetermined interval from one tunnel well of the existing tunnel to the other tunnel well, and correspond to the vibration receiving device. Same vibration place With shaker More than once The reflected wave according to the surrounding ground condition that touches the existing tunnel of the elastic wave generated by the vibration is received by the receiving device, and the reflected wave is analyzed to determine the surrounding geology of the existing tunnel. It is characterized by exploration.
[0034]
Between the one tunnel wellhead and the other tunnel wellhead is divided into a plurality of geological measurement sections, and the plurality of vibration receiving devices are installed by sequentially moving the plurality of geological measurement sections. It is characterized by being installed over the entire line. The vibration receiving device is installed on an underground passage surface of the existing tunnel and / or a lining concrete surface, and the vibration generating device vibrates by hitting the underground passage surface of the existing tunnel.
[0035]
The analysis is characterized in that at least a front reflected wave reflected from a front position from the front end of the front and rear ends of the measurement section and a back reflected wave reflected from a rear position from the rear end are used. The forward reflection is a forward reflected wave reflected from the immediately preceding measurement section adjacent to the front end of the measurement section, and the backward reflection is a backward reflected wave reflected from the immediately subsequent measurement section adjacent to the rear end of the measurement section. The ground condition for each measurement section is analyzed by superimposing the front reflected wave obtained by the measurement in the immediately following measurement section and the back reflected wave obtained by the measurement in the immediately preceding measurement section. Features. Such superposition may be performed, for example, by superimposing the front reflected wave and the back reflected wave on the same drawing.
[0036]
Geological exploration of an existing tunnel characterized in that the geological information obtained by the geological exploration method of an existing tunnel of any of the above configurations is used for pre-construction pre-investigation of construction for the existing tunnel such as widening construction Method.
[0037]
The present invention is a maintenance management method for an existing tunnel that determines whether or not the cause of tunnel degradation in an existing tunnel mine is based on ground conditions, and formulates maintenance measures for a tunnel degradation site based on the judgment, It is characterized in that it is determined whether or not the cause of tunnel degradation is based on ground conditions based on geological information obtained by applying the above existing tunnel geological exploration method.
[0038]
In the above-described configuration of the present invention, for example, a plurality of geophones are installed on the passage surface of an existing tunnel, and vibration is generated by a vibration device such as a hydraulic impactor corresponding to the vibration device installation location on the traffic surface. Safe geological exploration can be performed without using blast as the source. Because it is possible to use a small hydraulic exciter capable of self-propelled as a source of vibration, geological exploration of existing tunnels that are actually used for traffic is easily performed without significant traffic restrictions such as full road closure. be able to.
[0039]
By using a vibration generator such as a hydraulic impactor or a hydraulic vibrator as a vibration source, a vibration generator having a frequency characteristic in accordance with the natural ground characteristics can be adopted, and a more accurate ground in an existing tunnel. The situation can be grasped.
[0040]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIGS. 1A and 1B are explanatory diagrams showing the installation status of measuring instruments in a mine when performing geological exploration necessary for maintenance management of existing tunnels. FIG. 2 is a plan view schematically showing the state of FIG. 1 as viewed from above the tunnel.
[0041]
For example, the existing tunnel 10 shown in FIG. 1 is not in a state in which a long period of time has elapsed after construction and the geological survey result at the time of construction is easily available, but a geological survey for smooth maintenance and management of the tunnel 10 is performed. The case where it is necessary again is assumed. It is assumed that the tunnel 10 is routinely used as a road tunnel, and it is difficult to completely close the road for geological exploration.
[0042]
In the geological exploration method of the existing tunnel of the present invention, the geological exploration can be performed only in the other one-side lane while securing one-side traffic of the tunnel 10, that is, while allowing one-way traffic.
[0043]
As shown in FIGS. 1 and 2, in the section from one wellhead 11 a to the other wellhead 11 b of the tunnel 10, a survey section L as a plurality of measurement sections having the same length is provided on the entire tunnel along the laying direction of the tunnel 10. Set. In the case shown in FIGS. 1 and 2, only one survey line section L is shown for simplicity.
[0044]
As shown in FIG. 2, the survey line section L is set to one side lane in the tunnel as described above. Therefore, when the present invention is applied, it is not necessary to restrict the entire traffic in the tunnel, and one side traffic Just regulation. Such a state is shown in FIG. In FIG. 3A, the left side of the drawing is secured so that the vehicle W or the like can pass, and a survey line section L is set on the right side of the drawing to perform geological exploration.
[0045]
In the survey line section L, as shown in FIG. 1, a plurality of vibration receiving devices 12 are installed along the tunnel direction. The vibration receiving device 12 is installed in the survey section L at a predetermined interval on the traffic surface A along the tunnel direction. In the case shown in FIG. 1, for simplicity, a configuration in which eight vibration receiving devices 12 are arranged is shown. However, an appropriate pitch is set so that measurement data with good accuracy can be obtained, and it is commensurate with it. An appropriate number of vibration receiving devices 12 may be installed in accordance with the field conditions of the survey line section L.
[0046]
Several vibration receiving devices 12 are connected to one group by several, and each group is connected to a remote unit 13 which is an A / D converter. The remote units 13 are connected as shown in FIG. 1 and further connected to the recording / analyzing device 14.
[0047]
For the vibration receiving device 12, for example, a geophone (small seismometer) 12a having the configuration shown in FIG. 4 may be used. The geophone 12a is composed of a vibration receiving device main body 15a and a spike portion 15b that is detachably provided on the vibration receiving device main body 15a. Basically, the spike portion 15b is inserted into the measurement ground surface and the geophone 12a is connected to the geophone 12a. It is configured so that it can be fixed.
[0048]
Therefore, when the traffic surface A is non-paved, as shown in FIG. 4A, the spike portion 15b may be inserted and fixed as it is, but asphalt pavement or the like is applied. In this case, a mounting seat that can be stably placed on the passage surface A is provided once on the passage surface A, and the vibration receiving device main body 15a from which the spike portion 15b is removed is fixed and installed on the mounting seat.
[0049]
Signals from the plurality of vibration receiving devices 12 installed in this way are digitized by the remote unit 13 and then sent to the recording / analyzing device 14 for recording and analysis. As shown in FIG. 1B, the recording / analyzing device 14 is configured to issue an oscillation command in a wired or wireless manner to the vibration generating device 16 that vibrates in the vicinity of the vibration receiving device 12.
[0050]
For example, a hydraulic impactor shown in FIG. 5 may be used as the vibration generator 16. A small exciter that generates elastic waves can be used by hitting a grounding plate that is moved up and down in a hydraulic manner by colliding with the passage surface A. Or you may use vibrators, such as a hydraulic vibrator which can change the frequency of the elastic wave to generate | occur | produce by crimping | bonding the vehicle weight to the traffic surface A over a diaphragm.
[0051]
As shown in FIGS. 1 to 3, the vibration generating device 16 moves in the vicinity of the side of the plurality of vibration receiving devices 12 in order, and strikes the road surface A to generate elastic waves. The frequency of the generated elastic wave may be changed according to the natural ground conditions at the site. The frequency can be changed by selecting and using the vibration generating device 16 that generates an elastic wave suitable for the frequency.
[0052]
The vibration is performed corresponding to each of the plurality of vibration receiving devices 12 in the above-described manner. If necessary, vibration is performed a plurality of times (called stacking or superposition) at the same vibration generation location.
[0053]
The elastic waves generated by the vibration generating device 16 generating vibrations in the vicinity of each receiving device 12 propagate radially from the excitation point in the ground and are reflected at the boundary surface where the geology in the underground changes. The The reflected wave is received by the vibration receiving device 12, and the reflected wave is analyzed from the relationship between the elastic wave velocity and the reflection time, so that the location of the geological boundary surface can be known.
[0054]
The reflected wave received by the vibration receiving device 12 may be a reflected wave from a direction directly below the excitation point (hereinafter referred to as a reflected wave directly below), or a reflected wave from the ground in front of the excitation point (hereinafter referred to as the reflected wave). There is also a reflected wave from the inside of the ground at a position behind the excitation point (hereinafter referred to as a backward reflected wave).
[0055]
Therefore, the geological exploration in the survey line section may be performed from the analysis result of the direct reflected wave and the analysis result of the forward reflected wave and the backward reflected wave. As shown in FIG. 6 (A), the elastic wave generated from the excitation point of the roadbed surface A uses a direct reflected wave that is reflected by the geological boundary surface running along the roadbed surface A. Exploration of the horizontal structure of the geology directly below (hereinafter referred to as horizontal structure exploration).
[0056]
Further, as shown in FIG. 6B, the elastic wave generated from the excitation point of the roadbed surface A is reflected by the geological boundary surface running in the direction intersecting the roadbed surface A ahead of the excitation point. By using the reflected wave, the geological vertical structure in the survey section in front of the survey section where the vibration receiving device is installed can be explored. Similarly, the backward reflected wave can be used to search for a vertical structure in the rear survey line section (hereinafter referred to as a vertical structure search).
[0057]
That is, as shown in FIG. 6 (C), the horizontal structure of the geology using the direct reflection and the vertical structure of the geology using the forward reflected wave and the backward reflected wave are generated by the vibration in the survey line section. Each of the various structural conditions, and a comprehensive understanding of the geological situation can be obtained.
[0058]
When analyzing the forward reflected wave and the backward reflection, as shown in FIG. 7, the immediately preceding survey line L1 set adjacent to the front of the survey line segment L and the immediately following survey line set adjacent to the rear of the survey line segment L. It is possible to know the geological situation with the section L2. In the analysis of the reflection data shown in FIG. 7, the case where the reflection data directly under the survey line is omitted and the front reflection wave and the rear reflection wave are analyzed is shown. The superposition analysis of the front reflection wave and the rear reflection wave and the analysis of the direct reflection wave may be performed separately.
[0059]
Further, in the analysis of the reflection data, by using the reflected wave within the reflection time within a predetermined range, the acquired reflection data can be narrowed down only to the reflection data from the set immediately preceding line segment or just after the line segment.
[0060]
In FIG. 7, the survey line section L, the immediately preceding survey line section L1, and the immediately following survey line section L2 are taken on the horizontal axis assumed to be the entire tunnel line. On the lower side of the horizontal axis taking the survey line section L, the forward reflected wave reflected in the section corresponding to the immediately preceding survey line section L1 and the immediately following survey section L2 of the elastic wave generated by the vibration generator 16 in the survey line section L, the rear An analysis diagram F of the reflected wave is shown. In the analysis diagram F, the reflection time is taken in the vertical axis direction, and the installation points of the vibration receiving devices arranged in the survey line section L, that is, a plurality of vibration receiving points s may be taken in the horizontal axis direction. The number of reflected wave data corresponding to the number of receiving points s is acquired.
[0061]
Also, since the reflection time is short when reflected from a short distance and takes a long time when reflected from a long distance, if the reflection time is set to an appropriate range as described above, a preset section length is obtained. The analysis reflected wave can be narrowed down to only the reflected wave corresponding to the immediately preceding reflecting section L1 and the immediately following reflecting section L2. In FIG. 7, the state of the reflected wave is omitted from the central portion in the analysis diagram for simplicity.
[0062]
From the analysis of the forward reflected wave and the backward reflected wave, the boundary between the small geology of the reflective surface and the multi-surface of the reflective surface can be understood, that is, the existence of the boundary surface where the geology has changed from soft to hard and from hard to soft. You can see the geological situation of how long the soft zone and hard zone corresponding to the boundary surface are each continuing.
[0063]
Incidentally, as the installation interval of the vibration receiving device 12, in order to acquire data with good accuracy, the interval may be shortened, but a large number of vibration receiving devices 12 are installed accordingly. In the experiment, it was confirmed that accurate data acquisition was possible if it was installed in a straight line at intervals of 1.5 to 2 m. Of course, the installation interval may be set as appropriate in consideration of the situation in the field and the accuracy of the desired data.
[0064]
The analysis diagram F of the survey line section L in FIG. 7 schematically shows an analysis waveform group in which reflected waves other than the forward reflected wave and the backward reflected wave are removed as noise. A large number of reflected waves shown in the analysis waveform group indicate a front reflection wave and a back reflection wave received at a receiving point s corresponding one-to-one to a large number of excitation points shown on the horizontal scale of the analysis waveform group.
[0065]
FIG. 7 shows that each of the front reflected wave and the back reflected wave is excited at a plurality of times at each excitation point, and is generated at a separate excitation point different from the excitation point in a waveform superimposed by individual stacking. A superimposed waveform is shown in which a plurality of reflected waves obtained by shaking are subjected to position correction as performed at the excitation point and further superimposed.
[0066]
The reason why the two different stacking can be easily performed is that, in the present invention, a vibration generator capable of self-running is used as a vibration source without using blasting.
[0067]
As shown in FIG. 7, it can be seen that such an analysis waveform group includes a portion where a large wave x is continuously seen and a portion where a small wave y is continuously seen. By connecting the wave front at the boundary between the large wave x and the small wave y at each receiving point s with a straight line and extending the extrapolation line z toward the upper right side of the drawing (or the upper left side of the drawing), It is possible to predict the presence of a boundary surface between a relatively hard geology and a relatively soft geology in which forward reflection (or backward reflected wave) occurs. It can be determined that a portion where many large waves x are seen is relatively hard geology, and a portion where many small waves y are seen is relatively soft geology.
[0068]
In other words, if we read the intersection distance between the extrapolated line z connecting the wave front at the boundary between the part where many large waves x are seen and the part where many small waves y are seen, and the horizontal axis, If there is a boundary surface (geological boundary surface) between the soft portion and the hard portion of the geology from the survey line section L1, it can be roughly determined. FIG. 7 shows a case where the geological conditions before and after the survey line section L are zoned by the front reflection surface or the back reflection wave.
[0069]
The geological conditions of the immediately preceding survey segment L1 and the immediately following survey segment L2 determined in this way are shown on the horizontal axis of the corresponding segment. In FIG. 7, in the immediately preceding survey section L1, from the side close to the survey section L toward the front (in FIG. 7, toward the right side of the drawing), the reflective surface is less geological (hard) and the reflective surface is less reflective. A complex geological situation is frequently observed in which the geological situation frequently changes, such as a large number of reflective surface geology (soft), reflective surface minor geology (hard), reflective surface multiple geology (soft), and reflective surface minor geology (hard).
[0070]
On the other hand, in the immediately following survey line section L2, from the side close to the survey line section L toward the rear in order (in FIG. 7, toward the left side of the drawing), the reflective surface is less geological (hard), the reflective surface is multi-geological (soft), and the reflective surface. It can be seen that this is a relatively stable geological situation where minor geology (hard) repeats at almost equal intervals. Thus, from the survey in the survey line section L, the geological situation about the immediately preceding survey line section L1 and the immediately following survey line section L2 can be understood.
[0071]
When the geological survey in the survey line section L is completed in this way, the geological survey is performed by moving to the adjacent previous survey line section L2. In the present embodiment, since the plurality of survey line sections are set to the same length, the survey line section L and the previous survey line section L1 have the same length, and the same as when the vibration receiving device 12 is set in the survey line section L. The vibration receiving device 12 can be easily installed. The vibration receiving device 12, the remote unit 13, the recording / analysis device 14 and the like are set in the same manner as the survey line section L, and the vicinity of the plurality of vibration receiving devices 12 is sequentially excited by the vibration generating device. The geological survey of the survey line section L1 may be performed.
[0072]
In the geological survey in the survey line section L1, as in the survey line section L, the front reflected wave and the back reflected wave are analyzed, and the front previous survey line section L3 and the rear previous survey line section correspond to the previous survey line section L1. The geological survey of the survey line section L to be performed is performed. In this way, the vibration receiving device 12 is installed by sequentially moving a plurality of survey line sections, the data is acquired while receiving the reflected wave by exciting the vibration device 16 every time it is installed, and finally the tunnel Data can be acquired for all lines.
[0073]
In this way, while sequentially moving the survey line section, the geological data of the section immediately below, immediately before and immediately after the survey line section is acquired, and the geological situation of the entire tunnel line is analyzed by combining these geological data. It is shown in FIG. In FIG. 8, six blocks of survey sections a, b, c, d, e, and f are set along the entire tunnel line, and the above description is made by using reflected waves before and after sequentially moving each survey section. This shows how a geological survey is conducted in the manner described above.
[0074]
FIG. 8 shows how the geological situation obtained in each survey section is grasped from the data of the survey sections before and after the currently measured survey section. In the survey line section adjacent to the wellheads at both ends of the tunnel, the reflection of either the forward reflected wave or the backward reflected wave is obtained as data.
[0075]
That is, in the measurement in the survey section a in FIG. 8, the geological result of the survey section b corresponding to the previous survey section and the geological result of the section outside the tunnel wellhead are obtained as the forward exploration result A1. In the measurement in the survey line section b, the geological result of the survey line section c corresponding to the previous survey line section is obtained as the forward survey result B1, and the geological result of the survey line section a corresponding to the immediately subsequent survey section is obtained as the backward survey result B2.
[0076]
In the measurement in the survey line section c, the geological result of the survey line section d corresponding to the previous survey line section is obtained as the forward survey result C1, and the geological result of the survey line section b corresponding to the immediately subsequent survey section is obtained as the backward survey result C2. In the measurement in the survey section d, the geological result of the survey section e corresponding to the previous survey section is obtained as the forward survey result D1, and the geological result of the survey section d corresponding to the immediately subsequent survey section is obtained as the backward survey result D2.
[0077]
In the measurement in the survey section e, the geological result of the survey section f corresponding to the immediately preceding survey section is obtained as the forward survey result E1, and the geological result of the survey section e corresponding to the immediately following survey section is obtained as the backward survey result E2. In the measurement in the survey line section f, the geological result of the survey line section e corresponding to the immediately following survey section is obtained as the forward search result of the area outside the tunnel wellhead and the backward search result F2.
[0078]
In this way, except for tunnel both-end tunnel side survey sections (for example, corresponding to a and f in FIG. 8), the geological results of each survey section are A1 + C2, as shown in the analysis result below in FIG. As in B1 + D2, C1 + E2, D1 + F2, etc., it can be analyzed as a superposition of the forward search result and the backward search result. In the present invention, since the measurement data of both the front and rear of each survey line section can be combined, it is possible to perform a detailed geological survey with higher accuracy than when analyzing based on either one of the data. .
[0079]
Furthermore, in each survey section, in addition to the results of the vertical structure survey obtained from the front and back reflected waves, as described above, the result of the horizontal structure survey is also obtained from the direct reflected wave, so the analysis results from only the front and rear reflected waves More accurate geological exploration results.
[0080]
As shown in FIG. 9, by performing the analysis in the above manner, for example, it is confirmed that a crushing zone, a natural mountain fragile part, a geological boundary, or the like exists in front of the survey line section L, and in the rear. For example, the looseness of natural ground can be confirmed.
[0081]
In the geological exploration method of the existing tunnel of the present invention, as described above, since the geological exploration of the tunnel can be performed with a simple vibration device without restricting the entire traffic, the tunnel maintenance of the present invention incorporating such an exploration method is possible. The management method can devise appropriate maintenance measures against tunnel degradation safely in a short time without significantly hindering traffic even in trunk tunnels with a large traffic volume.
[0082]
In the above description, a plurality of survey line sections (measurement sections) are set in advance, and the reflected wave data is acquired in each survey line section each time by moving a set of a vibration receiving device or the like sequentially in each survey section, and the analysis However, for example, in the case of a short tunnel or the like, measurement may be performed by installing a vibration receiving device at predetermined intervals over the entire tunnel. In the analysis stage, a method of dividing and analyzing data into a plurality of survey line sections may be adopted. Of course, it is also possible to carry out the analysis without dividing the data into a plurality of survey line sections.
[0083]
In a long tunnel or the like, in order to install the vibration receiving device on all the lines at once, an extremely large number of vibration receiving devices are installed, and it may be difficult as a practical measure. As described above, if a plurality of survey line sections are set in advance and a limited number of vibration receiving devices are sequentially moved and measured, it is easy to handle the site.
[0084]
In such a case, for example, a plurality of sets of vibration receiving devices to be installed in the survey line section are prepared, and the vibration receiving device is advanced ahead of the front line segment while measuring with the current vibration generator. If you set, etc., you can continuously oscillate toward the survey section where you set the receiving device in advance without stopping the excitation work every time you set the receiving device Therefore, efficient geological exploration work can be performed.
[0085]
Next, the existing tunnel maintenance management method of the present invention will be described. The tunnel maintenance management method of the present invention is a method for appropriately performing maintenance and management measures based on the results of the above-described existing tunnel geological exploration method.
[0086]
Inspect the deterioration of the tunnel in detail by monitoring patrol across the entire tunnel. For example, the situation is recorded by carefully observing, for example, how much cracking has occurred in the lining concrete in the mine and whether there is no peeling of the concrete. When recording, use situation sketches or photography as appropriate.
[0087]
At the same time, the ground condition around the existing tunnel is performed according to the geological exploration method described above. Along the entire tunnel line, divide it into small sections and examine the ground conditions in detail. Such a small section may be the same as the survey line section partitioned by the geological exploration. The geological exploration described above is applied to evaluate the geological composition, ground strength, degradation range, ground bearing capacity, etc. for each survey section.
[0088]
The evaluation and the deterioration state of the tunnel obtained by the monitoring patrol or the like are summarized in a document format such as a tunnel deterioration investigation document or data that can be read and written by a computer in comparison with each surveying section. In summarizing, the geological situation and the degradation situation at the position can be quickly compared for each survey section along the entire line direction of the tunnel, for example, in m units or cm units.
[0089]
In addition, such a tunnel deterioration investigation document should be able to easily describe changes in deterioration and ground conditions in the future so that a comparison with time can be made quickly. By confirming the tunnel degradation survey report, the geology corresponding to the tunnel degradation site, for example, whether it is tuff, mudstone, or andesite, etc. should be known as soon as necessary.
[0090]
In this way, for example, it is possible to quickly determine whether tunnel deterioration such as cracks in lining concrete is based on external factors such as geological conditions or other internal factors. If it is determined that an external factor based on the surrounding ground conditions is the cause of the crack, whether or not the progress of the crack is recognized by comparing the cracks over time based on the tunnel deterioration survey report. to decide.
[0091]
When the progress of cracks is not substantially observed and it can be judged from the geological exploration results that the surrounding ground is stable, for example, an adhesive is injected into the crack in the lining concrete to prevent its expansion and separation It is judged that what is called repair measures, such as doing, should be taken.
[0092]
On the other hand, when the progress of the crack is recognized and the surrounding ground is not stabilized and the load bearing capacity of the tunnel structure is relatively lowered due to the influence thereof, the decrease in the load bearing capacity of the tunnel structure is suppressed, Alternatively, in order to improve the load bearing capacity, it is determined that structural reinforcement of the tunnel should be performed.
[0093]
In this way, in the existing tunnel maintenance and management method of the present invention using the above-described existing tunnel geological exploration method of the present invention, the cause of tunnel degradation is based on the geological exploration result obtained by the above-described geological exploration method. Judgment is due to the surrounding ground conditions of the tunnel, and if it is determined to be due to the ground conditions, is it possible to do the repair measures by comparing the tunnel degradation state and the ground conditions? Alternatively, it is possible to quickly and accurately determine whether or not a reinforcement measure on the tunnel structure is necessary.
[0094]
For this reason, a forward vibration wave, a rear reflection wave, etc. are used with a vibration method that strikes the road surface with a simple vibration device that can be moved without carrying out major traffic restrictions and without using blast vibration. Compared with the conventional existing tunnel maintenance management method that does not have a combination with the appropriate geological exploration method of the surrounding geological situation of the present invention that can perform detailed geological exploration, the maintenance management method of the existing tunnel according to the present invention, It is a very effective maintenance management method for the safety management of tunnels, which can accurately determine whether the cause of tunnel degradation is due to surrounding ground conditions.
[0095]
As described above, by using the geological exploration method of the present invention, it is possible to obtain geological information such as the ground conditions around the tunnel necessary for maintenance management of the existing tunnel. It can also be applied to geological surveys required for tunnel widening work. Hereinafter, this application method will be described.
[0096]
For example, as shown in FIG. 10, a case will be described below in which an existing tunnel 10 indicated by a broken line in the drawing is to be widened to the right side in view of the future traffic increase.
[0097]
As shown in FIG. 1, a plurality of geophones 12 a are used as vibration receiving devices 12 at predetermined intervals along the tunnel direction of the tunnel 10 so that the left side can be alternately passed toward the drawing of the tunnel 10. Install to form a survey line. The vibration receiving device 12 is installed close to the wall surface side of the tunnel 10, and is vibrated by the vibration generating device 16 on the side of each vibration receiving device 12. The vibration receiving device receives reflected waves and refracted waves of the generated elastic waves. 12 to receive the vibration.
[0098]
By applying the elastic wave refraction method together with the elastic wave reflection method to the data obtained in this way and analyzing the critical refracted wave on the data, geological information different from that obtained by the elastic wave reflection method can be obtained. Obtainable.
[0099]
The elastic wave radiated from the excitation point reaches the receiving point as a direct wave, reflected wave, or refracted wave, but when the elastic wave velocity below the surface layer is fast, it is refracted at the receiving point more than a certain distance away. It is observed as the wave that reaches the earliest (first movement). Therefore, at each receiving point, the running time, which is the initial movement arrival time, is plotted by the distance from the starting point to grasp the geological situation.
[0100]
In the analysis by the elastic wave reflection method, as shown in FIG. 11A, the time when the reflected wave returns and the reflection position (reflection depth, reflection location) can be known. Therefore, as compared with the elastic wave refraction method, as shown in FIG. 7, the existence position of the boundary surface where the elastic wave velocity at a deep depth changes from fast to slow, or from slow to fast is known. The specific reflected wave analysis geological structure corresponding to the change in the reflection intensity can be known.
[0101]
On the other hand, in the analysis by the elastic wave refraction method, as shown in FIG. 11 (B), the time when the refracted wave having a certain elastic wave velocity (Vp) returns is known. From this time, the distance between the receiving point and the starting point is known, and the velocity structure between the receiving point and the starting point is also known, and the specific geological structure is known from the velocity structure. In the analysis by the elastic wave refraction method, it is possible to know the refraction wave analysis geological structure captured as an elastic wave velocity zone at a shallower depth than the elastic wave reflection method.
[0102]
By using both the elastic wave analysis geological structure and the refraction wave analysis geological structure obtained by analyzing each of reflected waves and refracted waves in this way, continuous geological structure from shallow to deep depth of the ground surface Geological information about can be acquired. The analysis of the horizontal structure may be performed by analyzing the refracted wave from directly below the survey line, and the vertical structure may be analyzed by analyzing the refracted wave from the front or rear of the survey line.
[0103]
In the technical analysis of the cause of deterioration from the viewpoint of maintenance and management of existing tunnels, the geological information by the elastic wave reflection method is considered sufficient, but in the widening construction of existing tunnels that actually require excavation construction, The refraction wave analysis geological structure based on the elastic wave refraction method is useful geological information in addition to the reflected wave analysis geological structure.
[0104]
In the figure, the exploration region 17 in the widening direction of the tunnel 10 is indicated by a dotted line. A new widening tunnel 18 may be formed as shown in FIG. 10 based on both geological structure geological information related to the analysis of the reflected wave and the refracted wave in the exploration region 17.
[0105]
In the case shown in FIG. 12, the geological exploration situation when the existing tunnel 10 is widened in the left-right direction is shown. In this case, for example, the geological exploration on the right side may be performed with the left alternate traffic secured, and then the left geological survey with the right alternate traffic secured. In this way, the left and right horizontal and vertical geological information, which is the widening direction of the tunnel 10, can be obtained as described above.
[0106]
The present invention is not limited to the above-described embodiment, and may be changed as necessary without departing from the scope of the invention.
[0107]
For example, in the above description, the case where the method of vibrating the traffic surface with the vibration generator is described, but the side wall surface of the tunnel or, if possible, the ceiling surface may be vibrated. In addition, in the above description, the shape of the tunnel mine has been described assuming a vaulted tunnel. However, for example, as shown in FIG. Can do.
[0108]
For example, in the above description, one side lane is completely stopped and one side traffic is shown, but in long tunnels, traffic can be routed before and after the survey section, and only the survey section is avoided. If this is done, geological exploration can be performed in a more relaxed manner.
[0109]
In the above description, the case of a road tunnel has been described, but the same can be done for a railway tunnel. In this case, the vibration generator can be configured to be able to travel on railroad rails. Or it can also advance by shaking the shoulder side of a rail.
[0110]
It is also preferable to design a tunnel in which the installation space of the vibration receiving device and the space for the vibration generating point by the vibration generating device are provided in the tunnel in advance so that geological exploration can be performed as needed even after the opening. .
[0111]
Further, in the analysis, if it is judged that the information on the horizontal structure directly under the tunnel is not important depending on the condition of the surrounding natural ground, analyze the reflected waves before and after without analyzing the reflected waves directly under the tunnel. You may make it perform.
[0112]
The application of the present invention need not be limited to a mountain tunnel, and can also be applied to a submarine tunnel. In particular, in a submarine tunnel, a large water pressure is always applied, and it is impossible to neglect confirmation of a water discharge state into the tunnel, and it is also impossible to use blast vibration. Therefore, the application of the present invention is effective. The application is not limited to tunnels, but can also be applied to geological exploration of underground passages, caves, caves, etc., which have almost the same structure as tunnels.
[0113]
【The invention's effect】
According to the present invention, geological exploration of an existing tunnel can be performed using a vibration generating device that vibrates by hitting a traffic surface in a tunnel mine. In particular, since blast vibration is not adopted, it is possible to explore safely without damaging existing tunnels.
[0114]
In the present invention, unlike the case of blasting vibration, the frequency of the generated elastic wave can be changed in accordance with the natural ground condition by using the vibration generating device, and more accurate geological exploration is possible. In addition, unlike the case of blasting vibration, there is no restriction on the vibration position, so it is possible to select a free vibration position on the tunnel tunnel inner surface, ceiling surface, etc. as well as on the existing tunnel traffic surface.
[0115]
The installation position of the vibration receiving device may be any position in the tunnel mine, such as the tunnel passage surface or the vicinity of the side wall, and the degree of freedom of equipment installation is higher than blasting vibration. There is no need for drilling work at both the vibration generation position and the vibration reception position, making it easy to set up before measurement.
[0116]
In the present invention, by providing a plurality of measurement sections along the entire tunnel line and installing a plurality of excitation points and receiving points, it is forward from the excitation point as compared with the case of analyzing only with the reflected wave directly below. Since the reflected wave and the back reflected wave can be combined and analyzed, geological exploration with higher accuracy can be performed.
[0117]
Unlike blasting vibrations, individual stacking can be performed to oscillate a plurality of times at the same point. Therefore, even if the elastic wave energy is smaller than in the case of blasting vibrations, geological exploration can be performed with high accuracy.
[0118]
By using the vibration generator, the energy of the elastic wave to be generated can be kept small compared to the blasting vibration, and the proportion of the elastic wave transmitted is small even at a location relatively close to the vibration generating position. Then, it is possible to discriminate in detail the data of a relatively close vicinity section from the measurement section where the detailed search cannot be performed to about 100 m.
[0119]
Data with different measurement positions can be superimposed and evaluated in the same tunnel, and the measurement accuracy improves as the number of measurements increases. The first measurement data can be reflected in the second, third, and subsequent measurements.
[0120]
The geological exploration method of the existing tunnel of the present invention can be used as preliminary survey data for the geological survey of the widening work of the existing tunnel, and the geological survey in the widening work can be performed under a live line.
[0121]
In the existing tunnel maintenance management method of the present invention, since the geological exploration result based on the geological exploration method of the existing tunnel of the present invention is used, unlike the conventional case, it is possible to take highly accurate maintenance measures. In addition, the geological exploration method of the existing tunnel of the present invention is a method that does not use blasting vibrations, so that geological exploration can be performed without incurring a large cost, and there is no cost for many small tunnels. Maintenance management can be performed.
[Brief description of the drawings]
FIG. 1A is an explanatory diagram illustrating an example of an arrangement status of measuring devices in a tunnel to which the present invention is applied, and FIG. 1B is an explanatory diagram illustrating a connection status of a recording / analyzing apparatus.
FIG. 2 is a plan view showing vibration and receiving conditions in the tunnel mine.
FIGS. 3A and 3B are cross-sectional views showing a state in which geological exploration is performed while one-way traffic is performed in a tunnel mine.
4A is a cross-sectional view showing a state of installation of a vibration receiving device, and FIG. 4B is a perspective view showing a state of the vibration receiving device installed.
FIG. 5 is a side view showing a state in which vibration is generated using a vibration generator.
FIGS. 6A and 6B are explanatory views showing the state of horizontal structure exploration by direct reflected waves, FIG. 6B is an explanatory view showing the state of vertical structure exploration by front and rear reflected waves, and FIG. It is explanatory drawing which shows the exploration status of both horizontal structure exploration and vertical structure exploration in a section.
FIG. 7 is an explanatory diagram showing a usage state of an analysis diagram using a front reflected wave and a back reflected wave.
FIG. 8 is an explanatory diagram showing a procedure for performing geological exploration by dividing the entire tunnel line into a plurality of measurement sections.
FIG. 9 is an explanatory diagram showing an example of a geological situation determined from an analysis result.
FIG. 10 is an explanatory diagram showing a case where geological exploration for widening a tunnel in one direction is performed.
FIGS. 11A and 11B are schematic views showing a reflection state of elastic waves, and FIG. 11B is a schematic view showing a refraction state of elastic waves.
FIG. 12 is an explanatory diagram showing a case where geological exploration for widening a tunnel on both sides is performed.
[Explanation of symbols]
10 Tunnel
11a wellhead
11b wellhead
12 Vibration receiving device
12a Geophone
13 Remote unit
14 Recorder / Analyzer
15a Body of vibration receiving device
15b Spike part
16 Vibration generator
17 Exploration area
18 Widening tunnel
a Survey line section
b Survey line section
c Line segment
d Survey line section
e Survey line section
A traffic surface
A1 Forward search results
A2 Backward survey results
B1 Forward search results
B2 Backward search results
C1 forward search results
C2 backward search results
D1 Forward search results
D2 Backward search results
E1 forward search results
E2 backward search results
F1 forward search results
F2 backward search results
L Survey line section
L1 Previous survey section
Line section immediately after L2
L3 survey section
W vehicle

Claims (7)

A method of exploring the surrounding geology of an existing tunnel after opening,
Secure one side lane in the existing tunnel so that vehicles can pass,
On the other lane side in the existing tunnel , a plurality of vibration receiving devices are installed at a predetermined interval from one tunnel wellhead of the existing tunnel to the other tunnel wellhead,
Corresponding to the vibration receiving device, the same vibration location in the existing tunnel mine is struck multiple times with the vibration generating device,
The reflected wave is received by the vibration receiving device according to the surrounding natural ground conditions in contact with the existing tunnel of the elastic wave generated by the vibration,
A geological exploration method for an existing tunnel characterized by exploring the surrounding geology of the existing tunnel by analyzing the reflected wave. In the geological exploration method of the existing tunnel according to claim 1,
Between the one tunnel wellhead and the other tunnel wellhead is divided into a plurality of geological measurement sections, and the plurality of vibration receiving devices are installed by sequentially moving the plurality of geological measurement sections. A geological exploration method for existing tunnels, which is installed along the entire line. In the geological exploration method of the existing tunnel according to claim 2,
The vibration receiving device is installed on the underground tunnel surface and / or lining concrete surface of the existing tunnel,
The method for geological exploration of an existing tunnel, wherein the exciter vibrates by hitting the underground traffic surface of the existing tunnel. In the geological exploration method of the existing tunnel according to claim 2 or 3,
The analysis uses at least a front reflected wave reflected from a front position from the front end of the front and rear ends of the measurement section and a back reflected wave reflected from a rear position from the rear end. Tunnel geological exploration method. In the geological exploration method of the existing tunnel according to claim 4,
The forward reflection is a forward reflected wave reflected from the immediately preceding measurement section adjacent to the front end of the measurement section,
The back reflection is a back reflected wave that is reflected from the immediately following measurement section adjacent to the rear end of the measurement section,
The ground condition in each measurement section is analyzed by superimposing the front reflected wave obtained by the measurement in the immediately following measurement section and the back reflected wave obtained by the measurement in the immediately preceding measurement section. The existing tunnel geological exploration method.   The geological information obtained by the geological exploration method of an existing tunnel according to any one of claims 1 to 5 is used for a pre-construction pre-investigation of construction for the existing tunnel such as widening construction. The existing tunnel geological exploration method. It is a maintenance management method for an existing tunnel that determines whether the cause of tunnel degradation in an existing tunnel mine is based on ground conditions, and formulates maintenance measures for the tunnel degradation site based on the above judgment,
The determination as to whether or not the cause of tunnel degradation is based on ground conditions is based on geological information obtained by applying the existing tunnel geological exploration method according to any one of claims 1 to 5. A maintenance method for existing tunnels.

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